The effects of cells on oxygen transfer in bioreactors

Ju, Lu‐Kwang; Sundararajan, Anand

doi:10.1007/s004490050167

Cited by 5 publications

(10 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…E pp accounts for the physical presence of cells, considered as solid particles. Located in the gasliquid interface, this biotic solid phase results either in reducing oxygen transfer because of lower oxygen permeability of the cells compared with the abiotic phase (culture medium) [2,4,5], or in contrast, enhancing K L by hydrodynamic effects [6]. E qO 2 accounts for modifications generated by oxygen consumption.…”

mentioning

confidence: 98%

“…Key words Mass transfer Á Microbial culture Á Aeration Á Bioreactor List of symbols a interfacial area (dispersed interfacial area/V L ) (m -1 ) d 32 Sauter mean diameter (m) dO 2 dissolved oxygen, percentage of the saturation value e volumetric dissipated power (W m -3 ) E chem enhancement due to chemical modifications of the medium E pp enhancement due to the physical presence of cells as solid particles E qO 2 enhancement due to oxygen consumption H Henry's law constant (mol L -1 bar -1 ) k L oxygen transfer conductance in the liquid phase (m s -1 ) K L overall oxygen transfer conductance defined in the liquid phase (m s -1 ) K L,b overall oxygen transfer conductance defined in the liquid phase in biological medium (m s -1 ) K L a overall volumetric oxygen transfer coefficient defined in the liquid phase (s -1 ) K T overall volumetric oxygen transfer coefficient defined in the liquid phase in biological complex systems, (s -1 ) Q gas flow rate (L h -1 ) q O 2 volumetric oxygen consumption rate (mol L -1 h -1 ) R perfect gas constant RQ respiratory quotient T temperature (°K or°C) Us superficial gas velocity (m s -1 ) Enhancing microbial production represents an economic challenge for bioindustry. High performances in high cell density reactors imply controlling the interactions between microbial behaviour and transfer phenomena, since gas transfer eventually becomes a limiting factor.…”

mentioning

confidence: 99%

“…In biological systems when microbial dynamics occurs, enhancement factors accounting for biological modifications of gas transfer are implemented, and an overall oxygen transfer coefficient K T is defined [2]:…”

mentioning

confidence: 99%

“…E qO 2 accounts for modifications generated by oxygen consumption. Enhancement depends on the value of the oxygen transfer conductance, k L [7]: E qO 2 [ 1 in systems with low values of k L such as surface aerated cells [2,8,9], whereas (E qO 2 ¼ 1Þ in systems with high values of k L such as stirred tank reactors (STR) [10]. The main studies on oxygen transfer in microbial cultures are reported in Table 1.…”

mentioning

confidence: 99%

“…Works related to the use of dry cells resuspended in mineral media [2] to mimic cell cultures are very interesting as a starting point to understand mass transfer phenomena. But when the goal is the intensification of bioprocess performances in terms of productivity, further experiments and investigations are needed to elucidate biological and physical interactions in high cell density cultures.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Oxygen transfer in intensive microbial culture

Fyferling

Uribelarrea

Goma

et al. 2008

Bioprocess Biosyst Eng

View full text Add to dashboard Cite

Oxygen transfer performances in intensive microbial cultures are compared with those occurring in coalescing and non-coalescing mineral media. E. coli fed-batch cultures are carried out in a 22 L bioreactor. Biomass concentrations of 80 g(DW) L(-1) are reached, with oxygen consumption rates of up to 0.6 mol L(-1) h(-1). To achieve these high transfer performances, dissipated power e reaches 35 kW m(-3). The hold-up in the culture broth and in the corresponding supernatant matches the non-coalescing mineral medium. Oxygen transfer coefficients, K (L) a in mineral media, and K (T) in the culture broth, are compared. K (T), calculated online from a gas balance method, excesses 1 s(-1). Yet, for given values of e, K (T) is 4-8 times lower than K (L) a determined in the non-coalescing mineral medium. The cell activity modifies the chemical medium properties and reduces the oxygen transfer conductance, as in a non-coalescing ionic medium containing surfactant.

show abstract

mentioning

confidence: 98%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Oxygen transfer in intensive microbial culture

Fyferling

Uribelarrea

Goma

et al. 2008

Bioprocess Biosyst Eng

View full text Add to dashboard Cite

show abstract

Oxygen mass transfer and hydrodynamic behaviour in wastewater: Determination of local impact of surfactants by visualization techniques

et al. 2014

View full text Add to dashboard Cite

Powerful techniques, based on the Planar Laser Induced Fluorescence (PLIF) technique, are deployed to locally visualize and quantify the impact of surfactants in wastewaters on hydrodynamics and oxygen mass transfer. Bubble diameter, aspect ratio, rise velocity, contamination angle, as well as flux, flux density, liquid side mass transfer and diffusion coefficients of transferred oxygen are determined based on these techniques applied in the wake of rising bubbles of diameter 1 mm and through planar gas/liquid interfaces. The initial experiments were performed in demineralized water containing small amounts of surfactant. Different concentrations of surfactant were added to finally reach the Critical Micelle Concentration (CMC). Bubbles have classically been found to be more spherical with a reduced rise velocity in the presence of surfactants up to the CMC. Above the CMC, these hydrodynamic characteristics were found to be almost constant, although the oxygen mass transfer decreased due to the presence of surfactants. Experimental results were markedly lower than predicted by the well-known Frössling equation with rigid surfaces. This is believed to be caused by a barrier of surfactants hindering the oxygen mass transfer at the interface. Similar hindrance of oxygen mass transfer applies to waters from sewage plants (filtered raw water and treated water), making accurate design of aeration tanks difficult.

show abstract

Probe dynamics influence on determination of volumetric oxygen transfer coefficient

Niedzwiedz

Laszczyk

2014

2014 19th International Conference on Methods and Models in Automation and Robotics (MMAR)

View full text Add to dashboard Cite

This paper deals with practical aspects of volumetric oxygen transfer coefficient determination. The attention was paid to influence of dissolved oxygen probe dynamics on measurements. A new identification method of volumetric oxygen transfer coefficient was developed. This method involves numerical integral calculation. The new method and three other methods (graphical, logarithmic and regression) of determining volumetric oxygen transfer coefficient value were applied. The comparative simulation research was done using dissolved oxygen concentration model. All four methods were finally aplied to real biotechnological wastewater process with the activated sludge.

show abstract

The effects of cells on oxygen transfer in bioreactors

Cited by 5 publications

References 0 publications

Oxygen transfer in intensive microbial culture

Oxygen transfer in intensive microbial culture

Oxygen mass transfer and hydrodynamic behaviour in wastewater: Determination of local impact of surfactants by visualization techniques

Probe dynamics influence on determination of volumetric oxygen transfer coefficient

Contact Info

Product

Resources

About